Ion implantation is a standard technique for introducing impurities into semiconductor wafers. In an ion implantation process, a desired impurity material may be ionized in an ion source, ions from the ion source may be accelerated to form an ion beam of a prescribed energy, and the ion beam may be directed at a front surface of a semiconductor wafer. The energetic ions in the ion beam may penetrate into a bulk portion of the semiconductor wafer and may be embedded into a crystalline lattice of the semiconductor material. The ion beam may be distributed over an area of the semiconductor wafer by beam movement, by wafer movement, or by a combination of beam and wafer movement.
An ion implanter may have a terminal structure. The terminal structure may sometimes be referred to as a “terminal” or “high voltage terminal” and may be fabricated of conductive material such as metal. The terminal structure may have varying geometries that define a cavity and the ion source may be at least partially disposed within the cavity. The terminal structure may be energized to a terminal voltage to assist with acceleration of ions from the ion source. The terminal structure, as well as other components and sub-systems of the ion implanter, are typically surrounded by a grounded enclosure. The grounded enclosure may thus protect personnel from high voltage dangers when the ion implanter is running.
Air has conventionally been used to insulate the terminal structure from the grounded enclosure. However, there may be a constraint on the distance of the air gap between the terminal structure and the grounded enclosure since the size of the grounded enclosure is limited in volume manufacturing of semiconductor wafers. Accordingly, most conventional ion implanters limit the voltage of the terminal structure to about 200 kV.
In view of the foregoing, it may be understood that there are significant problems and shortcomings associated with current terminal structure technologies.